Band saw blade guide

ABSTRACT

A band saw blade guide includes a cylindrical chisel shaped member mounted at an oblique angle to a band saw blade. The blade guide adjusts the angle of the band saw blade by rotation of the guide about its axis. By rotating the guide about its axis, the angle of the chisel point guiding surface is changed thereby changing the angle of the blade. Further the blade may be guided by a single guide forced against one surface of the blade thereby eliminating the need for guides on both sides of the blade.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 11/414,934 filed May 1,2006 now U.S. Pat. No. 7,739,937.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION Field of Invention

This invention relates to adjustable guides used to maintain theposition of a band saw blade fixed relative to the band saw.

BACKGROUND OF THE INVENTION

Band saws have been around for years and various schemes have beendevised to guide the band saw blade so that the surfaces of the bladeare held parallel to the direction of feed of the material being cut.The most common scheme uses guiding members such as a bearing or blockof material that bears against the sides of the blades. These schemeshave limited adjustment. The position of the guide member is typicallyadjustable such that it may be adjusted closer or further away from theblade by an adjustment mechanism and also adjusted so that the edge ofthe guide member is closer to the teeth of the blade or further awayfrom the teeth of the blade. Typically no adjustment is provided for theangle of the blade. The angle of the blade is typically fixed by theaccuracy of the manufacture of the guide member. This lack of adjustmentfor the angle of the surface of the guide member requires both accuracyin manufacture of the guide mechanism and also requires replacement ofthe guide after it wears beyond acceptable limits.

Guides of prior art are provided on both sides of the blade in order tofully restrict the movement of the blade in the manner in which theseguide members are used.

BACKGROUND OF INVENTION Objects and Advantages

The object and advantage of the present invention are several fold.

Specifically:

(a) The present invention provides for a single simple adjustment tomove a blade guide towards or away from a band saw blade and also toguide the angle of the blade.

(b) The present invention allows for the use of a single guiding memberonly on one side of the blade.

(c) The present invention allows for adjustment to compensate forinaccuracies in manufacture of the blade guide mechanism.

(d) The present invention allows for adjustment to compensate for wearof the blade guide.

Further objects and advantages of the present invention will becomeapparent from the following descriptions and drawings.

SUMMARY

In accordance with the present invention a band saw blade guidecomprises a blade guide member formed in the shape of a cylindrical rodwith a chisel point. This blade guide member is held in a grove at anoblique angle to a side of the blade. A clamping means is provided tohold the blade guide member in a fixed position in the grove once theoptimal fixed position is determined. A means is provided to facilitaterotation of the guide member. In use the guide member is pressed againstthe blade and rotated such that the chisel point of the blade holds theblade in the desired position.

DRAWINGS Figures

In the drawings, closely related figures have the same numbers butdifferent alphabetic suffixes.

FIG. 1 shows a blade guide in its blade guide holder with associatedblade guide clamping bar and clamping bolts.

FIG. 2 illustrates 4 views of the blade guide.

FIG. 3 shows a portion of the entire band saw assembly with theassociated band saw parts.

FIGS. 4A and 4B illustrate the geometry of the blade guide with twodifferent adjustment positions.

REFERENCE NUMERALS

-   1 Blade guide-   2 Blade guide holder-   3 Blade guide clamping bar-   4 Blade guide clamping bolts-   5 Blade-   6 Band saw assembly-   7 Guide end of blade guide-   8 Adjustment hole-   9 Wheel-   10 Bearing

DETAILED DESCRIPTION

The blade guide 1 of the preferred embody is illustrated in FIG. 1. Theblade guide 1 is held in blade guide holder 2 by blade guide clampingbar 3. Clamping bar 3 is held firmly against the blade guide H byclamping bolts 4.

The details of the blade guide H are shown in FIG. 2. FIG. 2 illustratesthe blade guide 1 in four standard orthogonal views of a mechanicaldrawing. The Blade guide 1 is fabricated from a cylindrical rod of amaterial such as brass, which is strong yet softer than the steel fromwhich a band saw blade is made. The diameter of the rod is less than thewidth of the blade. The guide end 7 is fashioned to a chisel shape asillustrated. Adjustment hole S, in the opposite end of the blade guidefrom the guide end of the blade guide, receives a tool used to rotatethe blade guide about its axis during adjustment of the blade guide.FIG. 3 shows a portion of the entire saw assembly 6 with theinterrelation of parts. Wheel 9 supports the blade 5. Bearing HOprevents the blade 5 from being pushed off of wheel 9 when the blade 5is advanced through material being cut. Blade guide 1 is in a grove ofholder 2 and is held against the blade 5 by clamping bar 3. Clamp bolts4 hold the clamp bar 3 securely in place.

Before going on to how adjustments are made to the blade guide, adiscussion of details of a band saw is in order. Typically a wheel of aband saw as illustrated by wheel 9 in FIG. 3 does not have the surfaceon which blade rides formed as the surface of a cylinder. That is, thesurface is not cut parallel to the axis of the wheel. Typically thesurface is rounded like the tread surface of a donut shaped tire. Somedesigns have the surface on which the blade ride cut as the surface of atruncated cone, that is the surface is cut at an angle to the axis ofthe wheel. The purpose of these shapes is to cause the blade to stay onthe wheel as the wheel rotates. These shapes are very effective inkeeping the blade on the wheel. However these wheel shapes result in theblade not being supported their full width by the wheel. For instance,with the cone shaped wheel surface the blade is supported by the largerend of the truncated cone surface or typically the edge of the bladeaway from the teeth of the blade. Because of these shapes, the wheelalone cannot properly support the blade. In the cone shaped wheelsurface described above the edge of the blade away from the teeth is putunder greater tension the tooth edge of the blade and consequentlyreceive less support from the wheel. Because the tooth edge of the bladeis not supported as well as the back of the blade, the blade has atendency to wonder as the blade cuts through material. Because of thisproblem blade guides as discussed under prior art have been used. Theblade guides of prior art support on both sides of the blade to hold theblade parallel to direction of cut. The inventor has discovered that twoblade guides are unnecessary. One blade guide will properly support theblade provided that the blade guide has force against the blade. Thatis, force of the blade against the guide will hold the blade inalignment with the single blade guide, and thus parallel to thedirection of cut of the blade. Furthermore, the inventor has discoveredthat very little force of the blade guide against the blade is necessaryto hold the blade in alignment.

Accordingly, one novel principle incorporated into the present inventionis that a single blade guide forced against the blade will guide theblade.

A second novel principle is also incorporated into the presentinvention. Before proceeding to this principle, some background isnecessary. The inventor desired to have the band saw assembly <S asillustrated in FIG. 3 made by means of sand casting. Sand casting doesno lend itself to great accuracy in manufacture. As a consequence, ameans of adjustment of the angle of the blade guide was necessary. Tostate the problem another way, if a typical square in cross sectionblade guide had been used, there would be the possibility theimperfection in sand casting would cause the rectangular blade guide tobe out of the desired alignment with its desired position. Thismisalignment could result from any crude manufacturing process and couldalso result from wear of the blade guide. Thus, as will be seen from thefollowing discussion, the present invention provides adjustment of theangle of the blade guide.

FIGS. 4A and 4B illustrate how the geometry of the blade guide 1achieves the desired adjustment of the blade. In both figures only aportion of blade 5 is illustrated so as not to obstruct the view of theguide end 7 of the blade guide. The blade guide 1 is mounted at anoblique angle to the blade 5. In the illustration this angle isapproximately 60 degrees. Next referring to FIG. 4A, the blade guide 1is illustrated so that the viewer sees only the edge of the blade 5.

In other words the blade is adjusted so that the surface of the blade isperpendicular to the drawing surface. Next, assume that the angle of theblade S illustrated in FIG. 4 is not the desired blade position, but itis desired to position the blade so that the surface of the blade is notperpendicular to the drawing surface. FIG. 4 B illustrates the bladeguide having been rotated approximately ten degrees about its axis. Thisrotation of the blade guide 1 has resulted in the guiding surface beingapproximately five degrees to the drawing surface. The resultingposition of the blade 5 as illustrated in FIG. 4 B is approximately fivedegrees to the drawing surface. If some problem due to a defect inmanufacture or wear of the blade guide caused the blade not to be in thedesired position, rotation of the blade guide will correct the problem.This principle of rotation of a blade guide with the geometry shown isthe second novel feature of the present invention.

Referring back to FIG. 3, the process of adjustment of the blade guideis as follows:

The blade 5 is mounted on wheel 9 as illustrated. The blade guide 1 isinitially positioned so that it is not in contact with the blade 5. Thewheel 9 is caused to rotate and other adjustments not directly involvedwith the present invention are made. After adjustments are made so thatthe blade properly tracks on the wheel 9, the blade guide 11 may beadjusted. For safety reasons, without wheel 9 rotating blade guideadjustments are made. With clamp bolts 4 loosen, the blade guide 1 ispressed against the blade S. Simultaneously the blade guide 1 is rotatedthrough the use of a fool inserted info hole 8 until the blade is in thedesired position. Clamp bolts 4 are then tightened to hold the bladeguide H in place.

The inventor has illustrated the preferred embodiment of the invention.Other embodiments of the invention could be devised utilizing the novelprinciples as explained above. Such embodiments would fall within thescope and spirit of the present invention. Further, the inventor hasmade statements about blade tension and wheel geometry as his presentunderstanding of principles involved, however the inventor does not wishto be held to these because the point is: the blade guide of the presentinvention gives the desired results in the guiding the blade of a bandsaw blade.

1. A band saw comprising: a blade; a blade guide member; a blade guideholder for controlling blade angle, said blade guide holder comprising:a) a blade guide groove for receiving said blade guide member, saidblade guide groove oriented such that an extension of a longitudinalaxis of said blade guide groove intersects with said blade, and saidblade guide groove being at an oblique angle to the length direction ofsaid blade; b) said blade guide member being mounted in said blade guidegroove and pressed against said blade; c) means for securing said bladeguide member in said blade guide groove whereby said blade guide memberslides relative to said blade guide holder against said blade along alongitudinal axis of said blade guide holder and the entire blade guidemember rotates around said longitudinal axis of said blade guide holder,and said blade guide member is secured in said blade guide groove,thereby said rotation of said blade guide member adjusts the blade anglewith respect to a direction of cut so that said blade is parallel to thedirection of cut of said blade.
 2. A band saw comprising: a blade; awheel on which said blade is mounted; a blade guide member; a bladeguide holder for controlling blade angle, said blade guide holdercomprising: a) a blade guide groove for receiving said blade guidemember, said blade guide groove oriented such that an extension of alongitudinal axis of said blade guide groove intersects with said blade,and said blade guide groove being at an oblique angle to the lengthdirection of said blade; b) said blade guide member being mounted insaid blade guide groove and pressed against said blade; c) means forsecuring said blade guide member in said blade guide groove whereby,while said wheel is stationary, said blade guide member slides relativeto said blade guide holder against said blade along a longitudinal axisof said blade guide holder and the entire blade guide member rotatesaround said longitudinal axis of the said blade guide holder, and saidblade guide member is secured in said blade guide groove, thereby saidrotation of said blade guide member adjusts the blade angle with respectto a direction of cut so that said blade is parallel to the direction ofcut of said blade.